System and method for detecting gamma radiation, such as a gamma camera

a gamma camera and gamma radiation technology, applied in the field of gamma ray source imaging, can solve the problems of reducing the energy resolution, reducing the efficiency of gamma radiation detection, and only working suitably with very dense materials

Active Publication Date: 2015-11-19
ILTIS ALAIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patent describes a detection system that uses a module to compute the precise location of interactions in plates. This is done by intersecting temporal distribution vectors, the time of gamma ray impact on the plates, and spatial distribution vectors. The system is compact and can easily replace existing devices on known cameras. its technical effects include improved accuracy and efficiency in detection and improved accuracy in localization of interactions.

Problems solved by technology

One of the drawbacks of this technique is that it is costly to segment crystals into pixels, particularly for hydroscopic crystals.
Furthermore, this segmentation degrades the energy resolution.
Finally, this technology only works suitably with very dense crystals to prevent the Compton effect (BGO=Bismuth Germanate; LSO or LSO=Lutetium Silicate).
Furthermore, the spatial resolution in respect of SPECT is less than that in respect of PET due to a lack of precision in localising the interaction.
Consequently, it is not possible to attach two small plates to construct a larger one.
However, the current systems involve the following problems: 1) the scintillator must be segmented into pixels (4*4*30 mm for example) which is costly, 2) if the location of the interaction in the pixel is not known, this may generate geometric uncertainty which degrades image quality.
This further degrades the precision of the time of flight measurement, effectively limiting this measurement around 250 ps.
Systems have been proposed to measure the DOI (depth of interaction) on PET, but they are either unconvincing, or very costly (two detector layers).
Furthermore, the difficulty processing Compton events has led to very dense, generally Lithium-based, scintillators being sought, which are very costly.

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  • System and method for detecting gamma radiation, such as a gamma camera
  • System and method for detecting gamma radiation, such as a gamma camera
  • System and method for detecting gamma radiation, such as a gamma camera

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Embodiment Construction

[0024]The aim of the invention is that of proposing a system for detecting gamma radiation, such as a gamma camera, including a source of gamma rays, at least one plate P1 of a fast scintillator, the rise time thereof to the light peak being less than 1 ns with a scattering entry surface and a polished exit surface, having a thickness less than or equal to 10 mm, equipped with photodetectors and dedicated reading microelectronics, characterised in that the dedicated reading microelectronics are of the ASIC type, in that the detector is segmented, in that on said plate P1, each segment of said detector is suitable for measuring a first trigger T1, corresponding to the time of impact of the first UV ray emitted by scintillation onto said plate P1 such that a lower time resolution is less than 100 ps, preferably less than 20 ps, in that the detector is suitable for measuring a spatial and time distribution of the first adjacent photons emitted by an event on the detectors for a time of...

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Abstract

The invention relates to a system for detecting gamma radiation, such as a gamma camera, including a source of gamma rays, at least one plate P1 of a fast scintillator, the time thereof for rising to the light peak being less than 1 ns, said plate comprising a diffusing entry surface and a polished exit strike, having a thickness of no less than 10 mm, being provided with photodetectors and microelectronics for dedicated reading, characterised in that the microelectronics are of the ASIC type, in that the detector is segmented, and in that on said plate P1, each segment of said detector is capable of measuring a first trigger T1 such that a time resolution is lower than 100 ps; the detector can measure a space and time distribution of the first adjacent photons emitted by an event on the detectors for a time of more than 100 ps and no longer than the time for rising to the light peak of the scintillator. The invention further relates to the image-reconstruction method implemented in the system, as well as to the implementation and use of said system. The invention additionally relates to the image-reconstruction method and to the method for improving the energy resolution of the detector installed in the system, as well as to the implementation of said system.

Description

FIELD OF THE INVENTION[0001]The invention relates to gamma ray source imaging. More particularly, the invention relates to a system for detecting gamma radiation, based on a gamma camera, and the image-reconstruction method implemented in such a system. The invention further relates to the application of the detection system in the field particularly of astronomy and the medical field, and the application of said system to a PET or SPECT type imaging system.[0002]At the present time, gamma ray (>30 KeV) source imaging is essentially performed for medical diagnostic purposes based on two techniques: PET and SPECT.[0003]The SPECT (Single-Photon Emission Computerized Tomography) technique uses the emission imaging principle. In this case, it is sought to track the distribution of radioactive tracers emitting monoenergetic gamma photons inside an object to be analysed. The photon emission being isotropic, a collimator is placed in front of the camera to select the incoming direction ...

Claims

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Application Information

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IPC IPC(8): G01T1/208G01T1/29G06T7/00
CPCG01T1/208G06T7/0085G06T2207/10108G06T2207/10104G01T1/2985G01T1/1647G06T7/13
InventorILTIS, ALAIN
OwnerILTIS ALAIN